1. Field of the Invention
The present invention relates to a window blind assembly, more particularly to a window blind assembly that is used for covering a window and that includes a curtain control unit for bringing a curtain to fold upwardly and unfold downwardly.
2. Description of the Related Art
A conventional window blind assembly is disclosed in U.S. Patent Application Publication No. 2011/0203742. In FIG. 3 and FIG. 13 of the aforementioned publication, the window blind assembly includes a horizontal frame, a curtain member which has a top edge mounted at the horizontal frame and which includes a plurality of horizontally extending partitioning portions vertically spaced apart from each other, and a roller blind unit for bringing the curtain member to fold upwardly and unfold downwardly. The roller blind unit includes a horizontally extending roller rod mounted rotatably at the horizontal frame, a driving member operable to drive the roller rod to rotate about an axis of the roller rod, two roller blind pieces wound around and extended from the roller rod, two weighting rods each mounted to a bottom portion of the respective roller blind piece, and a plurality of connecting members each mounted on a respective one of the partitioning portions. Each of the connecting members and a corresponding one of the partitioning portions defines a slot therebetween for extension of the corresponding roller blind piece therethrough.
Each of the connecting members in the conventional window blind assembly has a confining portion in the form of a cloth strip, and two securing portions that connect the confining portion to a respective one of the partitioning portions. The securing portions may be realized through hook fasteners or loop fasteners.
For the purpose of maintaining dimensional stability of the slot, the confining portion is preferably stretched longitudinally prior to being fastened to the respective partitioning portion of the curtain member by means of the securing portions. Since the confining portion in the form of a cloth strip is substantially flexible, when the stretched confining portion contracts to its original length, the partitioning portion of the curtain member is brought to contract as well, such that the curtain member experience wrinkling and the appearance of the window blind assembly is adversely influenced. However, if the confining portion is loosely fastened to the partitioning portion, dimensions of the slot may be unstable, such that not only is the appearance of the curtain member adversely influenced but smooth folding and unfolding of the curtain member may be affected as well.